Bài giảng Data Communications and Networking - Chapter 7 Transmission Media

Chapter 7Transmission MediaCopyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display.1Figure 7.1 Transmission medium and physical layer2Figure 7.2 Classes of transmission media37-1 GUIDED MEDIAGuided media, which are those that provide a conduit from one device to another, include twisted-pair cable, coaxial cable, and fiber-optic cable.Twisted-Pair CableCoaxial CableFiber-Optic CableTopics discussed in this section:4Figure 7.3 Twisted-pair cable5Figure 7.4 UTP and STP cables6Table 7.1 Categories of unshielded twisted-pair cables7Figure 7.5 UTP connector8Figure 7.6 UTP performance9Figure 7.7 Coaxial cable10Table 7.2 Categories of coaxial cables11Figure 7.8 BNC connectors12Figure 7.9 Coaxial cable performance13Figure 7.10 Bending of light ray14Figure 7.11 Optical fiber15Figure 7.12 Propagation modes16Figure 7.13 Modes17Table 7.3 Fiber types18Figure 7.14 Fiber construction19Figure 7.15 Fiber-optic cable connectors20Figure 7.16 Optical fiber performance217-2 UNGUIDED MEDIA: WIRELESSUnguided media transport electromagnetic waves without using a physical conductor. This type of communication is often referred to as wireless communication.Radio WavesMicrowavesInfraredTopics discussed in this section:22Figure 7.17 Electromagnetic spectrum for wireless communication23Figure 7.18 Propagation methods24Table 7.4 Bands25Figure 7.19 Wireless transmission waves26Figure 7.20 Omnidirectional antenna27Radio waves are used for multicast communications, such as radio and television, and paging systems.Note28Figure 7.21 Unidirectional antennas29Microwaves are used for unicast communication such as cellular telephones, satellite networks,and wireless LANs.Note30Infrared signals can be used for short-range communication in a closed area using line-of-sight propagation.Note31